Stockholders' Equity (Summary of Warrants Outstanding) (Details)	3 Months Ended
	Mar. 31, 2019 $ / shares shares
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Warrants	26,480,505
Exercise Price 107.50 [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Warrants	41,872
Exercise Price | $ / shares	$ 107.50
Exercise Price 40.50 [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Warrants	31,519
Exercise Price | $ / shares	$ 40.50
Warrant Expiration Date	Mar. 31, 2021
Exercise Price 22.50 [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Warrants	106,381
Exercise Price | $ / shares	$ 22.50
Warrant Expiration Date	Jun. 03, 2021
Exercise Price 0.32 [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Warrants	168,498
Exercise Price | $ / shares	$ 0.32
Warrant Expiration Date	Nov. 22, 2021
Exercise Price 1.50 [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Warrants	7,920,933
Exercise Price | $ / shares	$ 1.50
Warrant Expiration Date	May 10, 2022
Exercise Price 0.40 [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Warrants	17,500,000
Exercise Price | $ / shares	$ 0.40
Warrant Expiration Date	Oct. 16, 2023
Exercise Price 0.01 [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Warrants	694,318
Exercise Price | $ / shares	$ 0.01
Warrant Expiration Date	Oct. 16, 2023
Exercise Price 120.00 [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Warrants	16,984
Exercise Price | $ / shares	$ 120.00